Which of the following is a nonpoint source of water pollution

"Rainwater pouring from an eroded bank into a river" is a non-point source of water pollution.

Explanation:

Bank erosion is the washing away of stream or river banks. This is distinct from erosion of the watercourse bed, known as scour. These erosion undermines the roots of trees which develop by a lake. As the roots closely connect the soil, they form abutments that jut out above the surface.

Non-point source water contamination is induced by widespread and isolated waste sources such as rain and snowmelt runoff, spills, leaks, and sediment erosions. To release any pollutant, without a permit, from a point source into navigable waters is illegal according to the Clean Water Act.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: